Extracorporeal device and method for removal of secondary membrane

Abstract

An extracorporeal blood treatment device and a method are provided for removing a secondary membrane formed on a semipermeable membrane of a dialyzer during an extracorporeal blood treatment. The extracorporeal blood treatment device operates in a first operating mode in which a dialysate outlet valve is open such that dialysate flows through a dialyzer feed line, through a dialysate chamber, and into and through a dialyzer discharge line. The extracorporeal blood treatment device operates in a second operating mode to remove the secondary membrane from the semipermeable membrane. During the second operating mode, the dialysate outlet valve is closed for a duration of time such that dialysate is prevented from flowing through the dialyzer discharge line. A backflush procedure results wherein a volume of dialysate passes from the dialysate chamber through the semipermeable membrane and into the blood chamber.

What is claimed is: 
     
         1 . A method of blood treatment comprising:
 providing an extracorporeal blood treatment device comprising a computing system, and a dialyzer having a blood chamber, a dialysate chamber, and a semipermeable membrane, the blood chamber and the dialysate chamber being divided from one another by the semipermeable membrane, the dialysate chamber comprising a dialysate outlet valve;   inputting device setting variables related to the extracorporeal blood treatment device into the computing system;   treating blood in a first operating mode by pumping dialysate through the dialysate chamber with a dialysate pump, pumping the blood through the blood chamber with a blood pump, and pulling ultrafiltrate out of the dialysate chamber with an ultrafiltrate pump;   detecting device output variables that accelerate a build-up of a secondary membrane on the semipermeable membrane while treating the blood in the first operating mode; and   after a time interval, switching from the first operating mode to a second operating mode, the second operating mode comprising closing the dialysate outlet valve for a duration of time and shutting off the ultrafiltrate pump, wherein   the closing of the dialysate outlet valve prevents dialysate from flowing out of the dialysate chamber and causes a volume of dialysate to pass from the dialysate chamber to the blood chamber through the semipermeable membrane,   the time interval (T i ) is calculated by the computing system according to an equation that modifies a preset base time (T B ) based on a product of predetermined coefficients of modification that are stored in the computing system,   the coefficients of modification that are stored in the computing system including at least one coefficient of modification that is based on at least one of the device setting variables (DSV) inputted into the computing system, and at least one coefficient of modification that is based on at least one device output variable (DOV), and   the method further comprises pre-programming into the computing system the at least one coefficient of modification that is based on the at least one device setting variable (DSV), and pre-programming into the computing system the at least one coefficient of modification that is based on the at least one device output variable (DOV).   
     
     
         2 . The method of blood treatment of  claim 1 , wherein the detecting of factors that lead to a build-up of a secondary membrane on the semipermeable membrane comprises detecting an increase in transmembrane pressure, which exceeds a preset percentage value. 
     
     
         3 . The method of blood treatment of  claim 1 , wherein
 the device setting variables that are inputted into the computing system and that are used to determine the coefficient of modification that is based on the at least one device setting variable are selected from: a type of dialyzer that is used during treatment; a type of treatment selected; a substitution pump rate; an ultrafiltration pump rate; a blood pump rate; whether substituate is provided to a blood line upstream or downstream of the dialyzer; a preset ultrafiltration coefficient associated with the dialyzer; an amount of hemodiafiltration bolus; and a combination thereof, and   the device output variables used to determine the coefficient of modification that is based on the at least one device output variable are determined using the sensor data and are selected from: a venous pressure; a transmembrane pressure; a change in ultrafiltration coefficient; a change in hematocrit; a change in transmembrane pressure; a change in clearance; and a combination thereof.   
     
     
         4 . The method of blood treatment of  claim 1 , wherein each of the dialysate pump and blood pump is operated at a respective first operating speed and at a respective second operating speed, and the dialysate pump and blood pump are run at their respective first operating speeds during the first operating mode and at their respective second operating speeds during the second operating mode. 
     
     
         5 . The method of blood treatment of  claim 1 , further comprising switching an ultrafiltrate pump between an operating state and a non-operating state, wherein, in the operating state, the ultrafiltrate pump pulls liquid from the blood chamber, through the semipermeable membrane, into the dialysate chamber, and away from the dialysate chamber, and the ultrafiltrate pump is switched to the non-operating state in the second operating mode. 
     
     
         6 . The method of blood treatment of  claim 1 , wherein the computing system runs an initial first operating mode phase for a primary operating time frame, the initial first operating mode phase starting at a beginning of priming, and the computing system switches the extracorporeal blood treatment device from first operating mode to the second operating mode once the operating time frame expires. 
     
     
         7 . The method of blood treatment of  claim 1 , wherein the computing system processes sensor data and switches the extracorporeal blood treatment device to the second operating mode from the first operating mode, for a time frame, based on the sensor data processed, the computing system runs an initial second operating mode phase for a primary operating time frame, the computing system switches the extracorporeal blood treatment device from the second operating mode to the first operating mode once the primary operating time frame expires, and the computing system modifies the primary operating time frame based on at least one device setting variable, at least one device output variable, or both. 
     
     
         8 . The method of blood treatment of  claim 1 , wherein the computing system processes sensor data and switches the extracorporeal blood treatment device to the second operating mode from the first operating mode, for a time frame, based on the sensor data processed, the computing system runs an initial second operating mode phase for a primary operating time frame, the computing system switches the extracorporeal blood treatment device from the second operating mode to the first operating mode once the primary operating time frame expires, and the computing system modifies the primary operating time frame based on at least one device setting variable and at least one device output variable. 
     
     
         9 . The method of blood treatment of  claim 1 , wherein
 the computing system alternates the extracorporeal blood treatment device between the first operating mode and the second operating mode in a series of a plurality of operating modes, and at a frequency, over a course of a treatment,   each of the plurality of operating modes comprises a respective operating time frame, and   the computing system modifies at least one of the frequency and each of the respective operating time frames, based on at least one device setting variable, at least one device output variable, or both.   
     
     
         10 . The method of blood treatment of  claim 1 , wherein an extracorporeal blood circuit is in fluid communication with the blood chamber, the extracorporeal blood circuit comprises the blood pump, the blood pump is controlled by the computing system, and the computing system reduces a pump speed of the blood pump during the second operating mode as compared to during the first operating mode. 
     
     
         11 . The method of blood treatment of  claim 1 , wherein the volume of dialysate that passes from the dialysate chamber through the semipermeable membrane and into the blood chamber is from 3 ml to 20 ml. 
     
     
         12 . The method of blood treatment of  claim 1 , further comprising:
 supplying fresh dialysate from a dialysate source through a balancing feed line and into a fresh dialysate side of a first balancing chamber of a balancing device;   moving spent dialysate from the dialysate chamber into a spent dialysate side of a second balancing chamber of the balancing device;   moving the fresh dialysate from the fresh dialysate side of the first balancing chamber into the dialysate chamber; and   discharging spent dialysate from the spent dialysate side of the second balancing chamber, through a discharge line, and into a drain.   
     
     
         13 . An extracorporeal blood treatment device comprising:
 a dialyzer comprising a blood chamber, a dialysate chamber, a dialysate inlet, a dialysate outlet, and a semipermeable membrane, the blood chamber and the dialysate chamber being divided from one another by the semipermeable membrane;   a dialyzer feed line that leads to the dialysate inlet and is configured to supply dialysate to the dialysate chamber;   a dialyzer discharge line that leads away from the dialysate outlet and is configured to carry dialysate away from the dialysate chamber;   a dialysate pump configured to pump dialysate through the dialyzer feed line to the dialysate chamber and from the dialysate chamber out through the dialyzer discharge line;   a dialysate outlet valve;   a blood pump configured to pump blood through the dialyzer to the blood chamber;   a computing system comprising a processor; and   a sensor in communication with the processor and configured to generate sensor data, wherein   the dialysate pump, the blood pump, or both, are configured to operate in a first operating mode of the extracorporeal blood treatment device and a second operating mode of the extracorporeal blood treatment device,   the first operating mode operates in a configuration wherein the dialysate outlet valve is open such that dialysate flows through the dialyzer feed line, through the dialysate chamber, and into and through the dialyzer discharge line,   the second operating mode operates in a configuration wherein the dialysate outlet valve is closed for a duration of time, dialysate is prevented from flowing through the dialyzer discharge line, and a volume of dialysate passes from the dialysate chamber through the semipermeable membrane and into the blood chamber,   the processor is configured to process the sensor data and to switch the extracorporeal blood treatment device to the second operating mode from the first operating mode, for a time frame, based on the sensor data processed,   the processor is configured to run an initial first operating mode phase for a primary operating time frame, the initial first operating mode phase starting at a beginning of treatment,   the processor is programmed to switch the extracorporeal blood treatment device from first operating mode to the second operating mode upon the expiration of a time interval,   the time interval (T i ) is calculated by the computing system according to an equation stored in the computing system and that is based on a base time (T B ) that the computing system automatically modifies dependent on a product of at least one coefficient of modification that is based on at least one device setting variable (DSV) that is entered into the computing system, and at least one coefficient of modification that is based on at least one device output variable (DOV),   the at least one coefficient of modification that is based on the at least one device setting variable (DSV) is pre-programmed into the computing system,   the at least one coefficient of modification that is based on the at least one device output variable (DOV) is pre-programmed into the computing system,   the device setting variables used to determine the coefficient of modification that is based on the at least one device setting variable are selected from: a type of dialyzer that is used during treatment; a type of treatment selected; a substitution pump rate; an ultrafiltration pump rate; a blood pump rate; whether substituate is provided to a blood line upstream or downstream of the dialyzer; a preset ultrafiltration coefficient associated with the dialyzer; an amount of hemodiafiltration bolus; and a combination thereof, and   the device output variables used to determine the coefficient of modification that is based on the at least one device output variable are determined using the sensor data and are selected from: a venous pressure; a transmembrane pressure; a change in ultrafiltration coefficient; a change in hematocrit; a change in transmembrane pressure; a change in clearance; and a combination thereof.   
     
     
         14 . The extracorporeal blood treatment device of  claim 13 , further comprising:
 a balancing device comprising a balancing chamber, a balancing feed line that leads to the balancing chamber and is configured to supply dialysate from a dialysate source into the balancing chamber, a balancing discharge line that leads away from the balancing chamber and is configured to carry dialysate away from the balancing chamber into a drain, wherein   the dialyzer feed line runs from the balancing chamber and is configured to supply dialysate from the balancing chamber to the dialysate chamber, and the dialyzer discharge line leads to the balancing chamber and is configured to supply dialysate from the dialysate chamber into the balancing chamber.